What's this vac line for ?

[StavTB48]

Hi all,

Could someone please tell me what this vac line is supposed to be plugged into? Obviously not the screw that's in the end :) also sorry for the bad photo... I decided to drive over my phone in the patrol:1087: ... camera didn't like it but the screen survived...

03 TB48 GU LPG/PET

It was tucked in hidden behind everything running along the firewall.

[BigRAWesty]

Can you chase to the other end?

[Avo]

time to go to a caryard and pop the bonnet mate..lol

[StavTB48]

Hi bigqwesty yep the second pic shows the solenoid that the line is coming from.. Didn't realise it was that bad and looking at it now I don't know why i would have thought anyone could have in the first place. Maybe this one might help.

wa 489 good idea i never thought of that then again i would still have no idea what its for or if its needed. Lol

[BigRAWesty]

Much easier to see lol.
Hopefully one of the 4.8 boys will chime in soon..
There's no issues atm with the car? Little things like excessive fuel usage? Or maybe a little under powered?
Or does the engine rpm increase a little at idle when the ac is turned on??

[StavTB48]

Thanks for the reply Kallen, only issue with the car at the moment is the throttle body error and tripping into limp mode... I picked up a new TB yesterday as i have now had two shops tell me it needs to be replaced and its yet to be fitted possibly next week. I'm resetting the fault codes every time it comes up.

Yes I am lacking some power however its not a huge amount but could be the result of me disconnecting the battery for a while whilst attemping to get out of limp mode before I got my hands onto a odb connector... I'm guessing this is unrelated as i might have lost my tune for running on the LPG. Its always run like a pig on Petrol since I have had it with what I would describe as like "turbo lag" on acceleration and is rough/chuggy on idle so not really drove it much on the petrol especially since i fitted a Flash lube system. Its still getting up and going but just a little more pedal is needed on the lpg than before.

Not sure on the fuel usage as not really made a good effort to keep track, I am getting roughly 280/300 K's as a guess to a tank of LPG I think its a 95L tank this is around the metro area varing from 50/70/100k's and traffic lights but not yet had a full run from full to empty on the LPG tank as of yet, no big tyres only 2 bars on the roof and a Steel oppisite lock bullbar. I was hoping to sort the throttle body issue out first and then find a good shop qualified for LPG to give the system looked over and tuned it is the older vapour type.

First Patrol and first time running on LPG so Ive dived into the deep end with this buy :)

[threedogs]

On another thread there was a reference to a perforated sheet behind
the maf sensor fitting , apparently if this gets holes it it things can get sluggish.
Might be worth a look
Pull that vacuum hose tight and move it around to see if any spare points it will
fit or another pipe blocked with a small piece of hose and a screw

[StavTB48]

Hi threedogs I do recall flicking past this post you mention a while back and mine has been removed as the gas converter is plonked in that corner of the engine bay, didnt think anything of it at the time but now you mention it i guess it could be linked to this, I will have a look and see if it mentions blocking a vac line.

[Fozzee63]

I recon it might be for the aircon Idle up vacuum sounds like the same position as mine on the drivers side firewall I had mine connected and disconnected it made very minute difference to idle rpm's, was reving up a bit to much for my likings

[BigRAWesty]

I recon it might be for the aircon Idle up vacuum sounds like the same position as mine on the drivers side firewall I had mine connected and disconnected it made very minute difference to idle rpm's, was reving up a bit to much for my likings

This was also my thinking but not sure how the newer tps setups worked in regards to the alight throttle increase.

[StavTB48]

Hi gents found some time but now its getting dark out so might have to have a another look tomorrow. I did however find the post that mentions the black ribbed box http://www.nissanpatrol.com.au/forums/showthread.php?31916-4-8-auto-power-loss-lazy-and-heavy-on-fuel&highlight=power+loss

The ribbed box shown in the pic from the above thread is non existing on mine as that's where my LPG mixer and all the pipes are. I cant see exactly but looks like there could be a vac line going into it or am I imagining this? Sill very interested in what it is and as originally asked and didn't answer in previous posts it doesn't seem to idle up when the Aircon is on so you guys could probably be on the money there and its not related to this box or is that what the ribbed box is there for?

Will get there eventually :)

Cheers

[BigRAWesty]

Well mate this is very interesting. If your correct and they have removed the maf sensor in aid of the gas install then that could very well be the reason for the shoit going on with the petrol.

Could we grab a bit of a full view pick of the engine bay. Like the stock one above??

[Bloggsy]

Hi mate, At a pretty reasonable guess, I'd say the previous owner has done what is known as the PVA Mod on another forum (which I've done myself, but slightly different). The vacuum hose end with the screw in it looks like it goes to the resonator (see diagram). Note that if you are going to undo this mod you will find that the actuator rod has been removed off the PVA and the PVA has been cable tied up. This will have to be put back on but you'll need an E clip and washer. I hope this helps.

http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=54845&stc=1http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=54846&stc=1

[threedogs]

Is this a common mod on petrol Patrols with Dual fuel ??

[BigRAWesty]

Hi mate, At a pretty reasonable guess, I'd say the previous owner has done what is known as the PVA Mod on another forum (which I've done myself, but slightly different). The vacuum hose end with the screw in it looks like it goes to the resonator (see diagram). Note that if you are going to undo this mod you will find that the actuator rod has been removed off the PVA and the PVA has been cable tied up. This will have to be put back on but you'll need an E clip and washer. I hope this helps.
Interesting read. It seems the 4.8's have a some what similar intake to the falcon 6's. A butterfly valve to increase the the length of the intake route and increase power.

[Bloggsy]

Is this a common mod on petrol Patrols with Dual fuel ??

Quite a few have done it, but it is not specific to dual fuels and only specific to the TB48's as far as I know. Mine is straight Petrol.

[StavTB48]

Blogsy looks like you are on the money there, the resonator is non existent and the vac line in the diagram is indeed the blocked line, unsure whats the go with the rod and PVA on mine as I haven't noticed anything out of place but guess i wasn't really looking for it. If this is a mod that people are doing or staring to do on the 4.8's and my PVA is cable tied up should I leave it all alone? I don't have the resonator or even know if one will fit back in so probably best huh. Is there any downside to this mod being done?

Bigwesty I may have been misleading on one of the posts as the maf is there :) not the best at explaining myself at the best of times haha. I'll try get some photo's up tomorrow, will have to look for my old digital camera. You never know you might be able to spot something else out that's in plain view as its not the tidiest engine bay i have owned and looks like some of the LPG wiring was cut and re crimped when the intake and head was off to fix a burnt valve before I purchased it as they didn't really make any effort to conceal/seal the connector's. (Is on the list to be sorted for the LPG service and tune after the new throttle body is on!) this is only a guess as I would be embarrassed if i was the gas installer and it was like it since it was fitted.

Keen to get car running right, missus wasn't impressed when I picked her up from work in it but in my defense I told her when i dropped her off that I was going to go buy one and the response was If its going to be more reliable I trust your judgement and now the issues I'm having its looking like a slippery slope haha so can't let it happen Ill never live it down!! Intended on spending some money on it as the rubber will need replacing later this year and maybe a 2" lift to get 31's under there was also considering a long range sub tank to be able to go further not relying on servo's with LPG as you get further out but need to sort it out before its even worth looking at these things and the long range sub would be pointless at the moment if its running this bad on petrol... not planning any trips soon that for sure baby steps for now :)

Can't complain too much tho.. someone I know has a V8 ford owned it from new just recently ticked out of the warranty so the tranny cooler in the radiator decided to fail last week and its 7K for a new box. OUCH.

Appreciate all the help guys!

[StavTB48]

On another note if you are interested in my babbling (highly doubt it, you might get a laugh at my expense tho) and know a thing or two about throttle body's there is another thread here: http://www.nissanpatrol.com.au/forums/showthread.php?31948-03-Y61-TB48-Throttle-Body-issues-part-number-and-couple-of-questions

Who the hell knows.. don't know what I'm going on about these days... too much :trink13: maybe.

[Bloggsy]

If the PVA mod is there you may as well just leave it there. I've had no issues with mine since doing almost 5 years ago.

[StavTB48]

Ok so had a look and the PVA is not disconnected and not cable tied open... I should now do so I guess ?

[BigRAWesty]

Ok so had a look and the PVA is not disconnected and not cable tied open... I should now do so I guess ?
So chase that line back from the valve to see if the vacuum part is still all connected.
If they've blocked the line but haven't disconnected the valve. Done a half ass job.

Good to hear about the maf though. Have you tried cleaning the maf sensor?? Might be an underling issue.

[StavTB48]

Hi Kallen,

Just had a good look and everything is connected at the valve end, vac line to the solienoid or what ever its called and then the vac line comming out with the screw in the end so I will have a look on the net for the tutorial for this mod sus it out and complete the job. There is a possibility that it was done and disconnected and a mech decided to "fix it" on the rod/valve end during its service I will have to ask him when he puts the new throttle body.

Good point on the MAF, im going to pick a can of MAF cleaner on the way home and give it ago, already read the thread on here and seems pretty strait forward.

Will let you guys know hwo i go.

[BigRAWesty]

Hi Kallen, Just had a good look and everything is connected at the valve end, vac line to the solienoid or what ever its called and then the vac line comming out with the screw in the end so I will have a look on the net for the tutorial for this mod sus it out and complete the job. There is a possibility that it was done and disconnected and a mech decided to "fix it" on the rod/valve end during its service I will have to ask him when he puts the new throttle body. Good point on the MAF, im going to pick a can of MAF cleaner on the way home and give it ago, already read the thread on here and seems pretty strait forward. Will let you guys know hwo i go.

So they started the mod but didn't finish it then. So yea up to you if you finish it or restore it back to factory. It sounds like the vac line just taps into the intake ducting but yea study the write ups.
Glad we got an out come and hopefully this will fix the petrol issue

[Bloggsy]

The mod is pretty simple, even I could do it. :)

1. Remove the 'E' clip and washer and slide the actuator rod off the PVA (Power Valve). Keep the 'E' Clip and washer somewhere safe in case you decide to undo the mod.
2. Disconnect the vacuum electrical connector that activates the solenoid (the one shown in your picture at the front of the solenoid). Some people blocked the vacuum line instead, like yours. I removed the connector, taped it up and cable tied it out of the way.
3. Turn the PVA clockwise to its maximum point and cable tie it in that position (as in picture).

[StavTB48]

Ok so MAF came out looking new but still gave it a clean did it over white cloth as in the thread on here and not much to be seen at all its back in so that's that, I have removed the bar from the PVA valve can cable tied it open, didn't completely fix the lagg whist cursing and roughness on the petrol but the response during take off is a lot smoother.

Didn't disconnect the battery at the time so will pop outside in a min and disconnect it for a little then a spin around the block. probably wont be able to tell much as from what i read after disconnecting the batt it can take a few k's to even everything out?

Cheers.

[BigRAWesty]

Ok so MAF came out looking new but still gave it a clean did it over white cloth as in the thread on here and not much to be seen at all its back in so that's that, I have removed the bar from the PVA valve can cable tied it open, didn't completely fix the lagg whist cursing and roughness on the petrol but the response during take off is a lot smoother. Didn't disconnect the battery at the time so will pop outside in a min and disconnect it for a little then a spin around the block. probably wont be able to tell much as from what i read after disconnecting the batt it can take a few k's to even everything out? Cheers. So we've found the blocked vac lines purposes. Hopefully this will help with the petrol tune

[StavTB48]

Hi Gent's, OK so thanks for solving my blocked vac line issue!!

Topped it up with gas and petrol with a few spins around the block then opening it up on the freeway and the lag and rough issue with the Petrol is still there and still not 100% the way it was on the gas so thinking its down to the throttle body and a tune.

Thanks again been much help!

[BigRAWesty]

Hi Gent's, OK so thanks for solving my blocked vac line issue!! Topped it up with gas and petrol with a few spins around the block then opening it up on the freeway and the lag and rough issue with the Petrol is still there and still not 100% the way it was on the gas so thinking its down to the throttle body and a tune. Thanks again been much help!

Sweet mate. I'd start with a tune to a good mechanic. Who knows what affect the valve was playing

[mudski]

See if there's any part numbers on the solenoid. Most Nissan parts will have the OEM number on them. Google it or pm me with what you find if you like and I can find out what it is.
If it helps.

[StavTB48]

Hi gent's just thought I would mention that I have reconnected the rod at the moment as boost or power when needed for example when overtaking on the freeway was lacking or better described as a bit slow to pick up speed when already doing 90/100. Still haven't had it tuned yet as my fault code saga continues and looking like money spent on a new throttle body might have been a waste of time/money. Maybe one day if its fixed without replacing everything under the bonnet ill find out if there is any benefit having the pva mod done on my truck.

Cheers.

[BigRAWesty]

That's a shame mate. Nothing worse than forking out the hard earned and it not working. If it was me I'd run with the pva mod and new throttle body and now have it tuned. But you'll never get 100% on both gas and petty. There are 2 different fuels and if set right for one the other will have issues.